534 U.S. 112 (2001)
A California court sentenced respondent Mark James Knights to summary probation for a drug offense.1 The probation order included the following condition: that Knights would submit his person, property, place of residence, vehicle, personal effects, to search at anytime, with or without a search warrant, warrant of arrest or reasonable cause by any probation officer or law enforcement officer.2 Knights signed the probation order, which stated immediately above his signature that he had received a copy, read and understood the above terms and conditions of probation and agreed to abide by same.3
Three days after Knights was placed on probation, a Pacific Gas & Electric power transformer and adjacent Pacific Bell telecommunications vault near the Napa County Airport were pried open and set on fire, causing an estimated $1.5 million in damage.4 Brass padlocks had been removed and a gasoline accelerant had been used to ignite the fire.5 This incident was the latest in more than 30 recent acts of vandalism against PG&E facilities in Napa County.6 Suspicion for these acts had long focused on Knights and his friend, Steven Simoneau.7
After the PG&E arson, a sheriff’s deputy drove by Knights’ residence, where he saw Simoneau’s truck parked in front.8 The deputy felt the hood of the truck. It was warm.9 Detective Hancock decided to set up surveillance of Knights’ apartment.10 At about 3:10 the next morning, Simoneau exited the apartment carrying three cylindrical items.11 Detective Hancock believed the items were pipe bombs.12 Simoneau walked across the street to the bank of the Napa River, and Hancock heard three splashes.13 Simoneau returned without the cylinders and drove away in his truck.14 Simoneau then stopped in a driveway, parked, and left the area.15 Detective Hancock entered the driveway and observed suspicious objects in the truck: a Molotov cocktail and explosive materials, a gasoline can, and two brass padlocks that fit the description of those removed from the PG&E transformer vault.16
After viewing the objects in Simoneau’s truck, Detective Hancock decided to conduct a search of Knights’ apartment.17 Detective Hancock was aware of the search condition in Knights’ probation order and thus believed that a warrant was not necessary.18 The search revealed a detonation cord, ammunition, liquid chemicals, instruction manuals on chemistry and electrical circuitry, bolt cutters, telephone pole-climbing spurs, drug paraphernalia, and a brass padlock stamped PG&E.19 Knights was arrested, and a federal grand jury subsequently indicted him for conspiracy to commit arson, for possession of an unregistered destructive device, and for being a felon in possession of ammunition.20 Knights moved to suppress the evidence obtained during the search of his apartment.21 The District Court held that Detective Hancock had reasonable suspicion to believe that Knights was involved with incendiary materials.22 The District Court nonetheless granted the motion to suppress on the ground that the search was for investigatory rather than probationary purposes.23 The Court of Appeals for the Ninth Circuit affirmed.24 The Supreme Court granted certiorari to assess the constitutionality of searches made pursuant to this common California probation condition.25
Whether a search pursuant to this probation condition, and supported by reasonable suspicion, satisfied the Fourth Amendment?26
The touchstone of the Fourth Amendment is reasonableness, and the reasonableness of a search is determined by assessing, on the one hand, the degree to which it intrudes upon an individual’s privacy and, on the other, the degree to which it is needed for the promotion of legitimate governmental interests.27 Knights’ status as a probationer subject to a search condition informs both sides of that balance.28 Inherent in the very nature of probation is that probationers do not enjoy the absolute liberty to which every citizen is entitled.29 The very assumption of the institution of probation is that the probationer is more likely than the ordinary citizen to violate the law.30
Yes. The probation condition significantly diminished Knights’ reasonable expectation of privacy.31 The condition was clearly expressed in the probation order.32 Knights was unambiguously informed of it when he signed the order.33
The government’s interest is substantial because probationers have a significantly higher recidivism rate than the general population.34 Probationers also have a greater incentive to conceal criminal activities.35 The observations of the warm truck hood, the splashes at the river, and the suspicious objects in the truck including the matching padlocks and Molotov cocktail established the requisite reasonable suspicion that Knights was engaged in criminal activity.36 The District Court held that Detective Hancock had reasonable suspicion to believe that Knights was involved with incendiary materials.
The District Court nonetheless granted the motion to suppress on the ground that the search was for investigatory rather than probationary purposes. The warrantless search of Knights, supported by reasonable suspicion and authorized by a condition of probation, was reasonable within the meaning of the Fourth Amendment.37
The search satisfied the Fourth Amendment.38
Related opinions on this issue
Justice Souter concurred in the judgment. As this case was originally presented to us, the dispute centered on whether Knights’s agreement to the search condition included in his terms of probation covered only those searches with a probation-related purpose, or rather extended to searches with an investigatory or law-enforcement purpose.39 We now hold that law-enforcement searches of probationers who have been informed of a search condition are permissible upon individualized suspicion of criminal behavior committed during the probationary period, thus removing any issue of the subjective intention of the investigating officers from the case.40
Justice Souter would therefore reserve the question whether Whren’s holding, that “Subjective intentions play no role in ordinary, probable-cause Fourth Amendment analysis,” should extend to searches based only upon reasonable suspicion.